The Poison Prevention Packaging Act of 1970 has caused a great expansion of the use of child resistant closures on multi-use containers. Obviously, these containers are opened and closed many more times by the user of the contents than by the original packager who usually applies the closure with an application torque which will properly protect the contents. Great difficulty has been encountered by older persons when they try to open child resistant caps on prescription drugs. A survey of 2000 randomly selected pharmacist members of the American Pharmaceutical Association showed that of their customers 84.6 percent found that the problem of opening the containers with great difficulty occurred "often" or "very often". More than half found "often" or "very often", that the customers were unable to open the safety containers without assistance. Some of these people found the difficulty to be so great that they would deliberately break the container and/or the cap and more than half of them would leave the container open or with the safety feature disengaged or would transfer the medicines to another container. Frequently, the contents of the container would be spilled or otherwise lost by the customers while opening a child resistant container.
Many of the medicines packaged in these containers deteriorate upon prolonged exposure to air or moisture and the most common of the child resistant closures makes no attempt to overcome this problem of repeatedly opening and closing a container to form a "tight" seal between the vial in which the medicine is contained and the closure itself. In some forms of medicine a shelf life of 25 days to fifty days is expected when the medicine is in the hands of the pharmacist but this is reduced to two to five days when the same medicine is in a child resistant closure which cannot be tightly closed. It has been recognized that a screw threaded closure is best suited to protect the contents of a container against deterioration. The present invention provides a screw threaded inner member for the child resistant closure which can be tightly closed with a minimum of application torque.